Oklahoma Wastewater Operator Class
C Exam Practice Questions And
Correct Answers (Verified Answers)
Plus Rationale 2027 Q&A| Instant
Download Pdf.
1. Which statement best describes the primary purpose of a municipal
wastewater treatment system?
A. To increase the mineral content of receiving waters
B. To remove or reduce pollutants so treated effluent can be discharged
or reused in accordance with applicable requirements
C. To convert all wastewater into potable drinking water
D. To eliminate the need for collection-system maintenance
Answer: B. To remove or reduce pollutants so treated effluent can be
discharged or reused in accordance with applicable requirements
Wastewater treatment is intended to reduce pollutants and protect
public health and the environment by producing an effluent that meets
applicable discharge requirements.
, 2. Oklahoma wastewater operator certification examinations are
structured around multiple areas of competency. Which group of
subjects is specifically emphasized for a Class C wastewater
operator?
A. Only laboratory chemistry and advanced tertiary treatment
B. Collection systems, safety, preliminary and primary treatment,
secondary treatment, ponds, regulations, and other core operating areas
C. Only administrative management and personnel supervision
D. Only sludge incineration and advanced nutrient recovery
Answer: B. Collection systems, safety, preliminary and primary
treatment, secondary treatment, ponds, regulations, and other core
operating areas
The Oklahoma DEQ study guide identifies multiple competency areas,
with Class C placing substantial emphasis on regulations, collection
systems, safety, preliminary and primary treatment, secondary
treatment, ponds, and other operational subjects.
3. What is the principal reason screening is used at the beginning of
many wastewater treatment processes?
A. To increase dissolved oxygen concentration
B. To remove large floating and suspended debris that could damage
downstream equipment
C. To biologically nitrify wastewater
D. To disinfect the final effluent
,Answer: B. To remove large floating and suspended debris that could
damage downstream equipment
Screens intercept rags, sticks, plastics, and other large materials before
they can interfere with pumps, valves, clarifiers, aeration equipment,
and other downstream processes.
4. What is the primary function of a grit-removal process?
A. Remove readily settleable inorganic particles such as sand and gravel
B. Remove dissolved ammonia biologically
C. Destroy pathogenic organisms
D. Convert nitrate directly into oxygen
Answer: A. Remove readily settleable inorganic particles such as sand
and gravel
Grit removal protects downstream equipment and reduces unwanted
accumulation by removing dense inorganic solids that settle more
rapidly than typical organic wastewater solids.
5. A wastewater flow entering a treatment plant contains an unusually
large amount of grease and floating material. Which preliminary
treatment equipment is particularly important for controlling this
material?
A. Chlorine contact basin
B. Bar screen or skimming equipment
, C. Ultraviolet reactor only
D. Sludge digester
Answer: B. Bar screen or skimming equipment
Screens can capture larger debris, while properly designed skimming or
grease-removal processes can remove floating fats, oils, and grease
before they interfere with downstream treatment.
6. Which wastewater characteristic is most directly associated with
the amount of oxygen required to biologically oxidize
biodegradable organic matter?
A. Biochemical oxygen demand
B. Total dissolved solids
C. Alkalinity
D. Conductivity
Answer: A. Biochemical oxygen demand
Biochemical oxygen demand, or BOD, estimates the oxygen consumed
by microorganisms while biologically decomposing biodegradable
organic matter under specified test conditions.
7. Why is excessive BOD in final effluent a concern when discharged to
a receiving stream?
A. It can consume dissolved oxygen in the receiving water
B. It always increases water hardness
C Exam Practice Questions And
Correct Answers (Verified Answers)
Plus Rationale 2027 Q&A| Instant
Download Pdf.
1. Which statement best describes the primary purpose of a municipal
wastewater treatment system?
A. To increase the mineral content of receiving waters
B. To remove or reduce pollutants so treated effluent can be discharged
or reused in accordance with applicable requirements
C. To convert all wastewater into potable drinking water
D. To eliminate the need for collection-system maintenance
Answer: B. To remove or reduce pollutants so treated effluent can be
discharged or reused in accordance with applicable requirements
Wastewater treatment is intended to reduce pollutants and protect
public health and the environment by producing an effluent that meets
applicable discharge requirements.
, 2. Oklahoma wastewater operator certification examinations are
structured around multiple areas of competency. Which group of
subjects is specifically emphasized for a Class C wastewater
operator?
A. Only laboratory chemistry and advanced tertiary treatment
B. Collection systems, safety, preliminary and primary treatment,
secondary treatment, ponds, regulations, and other core operating areas
C. Only administrative management and personnel supervision
D. Only sludge incineration and advanced nutrient recovery
Answer: B. Collection systems, safety, preliminary and primary
treatment, secondary treatment, ponds, regulations, and other core
operating areas
The Oklahoma DEQ study guide identifies multiple competency areas,
with Class C placing substantial emphasis on regulations, collection
systems, safety, preliminary and primary treatment, secondary
treatment, ponds, and other operational subjects.
3. What is the principal reason screening is used at the beginning of
many wastewater treatment processes?
A. To increase dissolved oxygen concentration
B. To remove large floating and suspended debris that could damage
downstream equipment
C. To biologically nitrify wastewater
D. To disinfect the final effluent
,Answer: B. To remove large floating and suspended debris that could
damage downstream equipment
Screens intercept rags, sticks, plastics, and other large materials before
they can interfere with pumps, valves, clarifiers, aeration equipment,
and other downstream processes.
4. What is the primary function of a grit-removal process?
A. Remove readily settleable inorganic particles such as sand and gravel
B. Remove dissolved ammonia biologically
C. Destroy pathogenic organisms
D. Convert nitrate directly into oxygen
Answer: A. Remove readily settleable inorganic particles such as sand
and gravel
Grit removal protects downstream equipment and reduces unwanted
accumulation by removing dense inorganic solids that settle more
rapidly than typical organic wastewater solids.
5. A wastewater flow entering a treatment plant contains an unusually
large amount of grease and floating material. Which preliminary
treatment equipment is particularly important for controlling this
material?
A. Chlorine contact basin
B. Bar screen or skimming equipment
, C. Ultraviolet reactor only
D. Sludge digester
Answer: B. Bar screen or skimming equipment
Screens can capture larger debris, while properly designed skimming or
grease-removal processes can remove floating fats, oils, and grease
before they interfere with downstream treatment.
6. Which wastewater characteristic is most directly associated with
the amount of oxygen required to biologically oxidize
biodegradable organic matter?
A. Biochemical oxygen demand
B. Total dissolved solids
C. Alkalinity
D. Conductivity
Answer: A. Biochemical oxygen demand
Biochemical oxygen demand, or BOD, estimates the oxygen consumed
by microorganisms while biologically decomposing biodegradable
organic matter under specified test conditions.
7. Why is excessive BOD in final effluent a concern when discharged to
a receiving stream?
A. It can consume dissolved oxygen in the receiving water
B. It always increases water hardness
